The present invention relates to actuators and more particularly to height adjustment mechanisms for furniture and other articles.
Various forms of telescoping actuators are presently available for supporting a load and adjusting the position of the load relative to a base. In furniture applications, such actuators may be used with chairs, tables, work surfaces and the like. Currently available actuators include hydraulic, pneumatic, pressurized gas or mechanical adjusters. Available structures may have a limited range of motion. Many suffer from excess complexity.
In the seating area, actuators or support columns are used to set the vertical height of the seat to adjust the seating to the user and/or the task. Currently available actuators include weight actuated height adjusters of the type disclosed in commonly owned U.S. Pat. No. 4,709,894 entitled SLIP CONNECTOR FOR WEIGHT ACTUATED HEIGHT ADJUSTERS, which issued on Dec. 1, 1987 to Knoblock et al. The adjuster disclosed therein is functional when the seat is unoccupied. The actuator disengages when the seat is occupied to permit the seat to swivel on the base without an effect on the seat height. Examples of pneumatic or gas spring adjustment mechanisms may be found in U.S. Pat. No. 5,078,351 entitled ADJUSTABLE LENGTH CYLINDER SUPPORT PILLAR FOR CHAIR SEAT, which issued on Jan. 7, 1992 to Gualtieri and U.S. Pat. No. 4,580,749 entitled SUPPORT COLUMN UNIT, which issued on Apr. 8, 1986 to Howard.
Available height adjustment mechanisms have limited travel range. Currently available seat actuators are not capable of raising the seat height from a standard seated use position to a standing use position. Currently available mechanisms cannot be modified to provide increased travel while maintaining a compact configuration and smooth and quiet operation. A need, therefore, exists for an improved actuator capable of adjusting the positioning of a load and which may be readily incorporated into existing articles such as furniture.